Process for the production of titanium and zirconium hydrogen peroxide products



United States Patent 3,139,325 PROCES FOR THE PRODUCTION OF TITANIUM AND ZIRCONIUM HYDROGEN PEROXIDE PRODUCTS K 7i Takada, Shinjuku-ku, Tokyo, Japan, assignor to Toyo Kinzokukagaku Kabushikikaisha, Tokyo, Japan No Drawing. Filed Mar. 6, 1961, Ser. No. 93,326 Claims priority, application Japan Jan. 28, 1961 4 Claims. (Cl. 23-14) The invention relates to a novel process for the production of titanium and zirconium compounds, for use in the formation of alloy coatings consisting of cadmium or zinc, on the one hand, and titanium or zirconium, on the other hand.

It has been already proposed by me to produce alloy coatings of the kind above referred to in such a way that a pertitanate and a perzirconate is dissolved in a conventional coating bath containing cadmium cyanide or zinc cyanide and the electrolysis is carried out with use of cadmium or zinc as anode.

The main object of the invention is to provide a novel process for the production of titanium and zirconium compound, especially adapted to add to the coating bath in the above proposed coating process.

Tetrahyroxide of titanium or zirconium can be obtained, when a solution of tetravalent salts of titanium or zirconium, such as, for instance, titanium tetrafluoride, zirconium tetrafluoride or the like, is subjected to a hydrol ysis in the presence of an alkali. The thus obtained tetrahydroxides are variable in their chamical and physical properties, depending upon the temperature and other conditions during the hydrolysis to a substantial degree. Thus, there are a plurality of isomers of tetrahydroxides of titanium and zirconium. It is, therefore, the more specific object of the invention to provide a novel process for the production of such titanium or zirconium tetrahydroxide which easily reacts with hydrogen peroxide to form the corresponding addition product liable to solve stably in an alkaline solution and thereby to form the pertitanate or perzirconate. According to my profound experiments, salts of strong acids, such as,

for instance, the fluorides, chlorides, sulphates and the like are preferably used as the above mentioned tetravalent salts of titanium or zirconium, while salts of weak acids are liable to be subjected to hydrolysis and thus to form an unwanted titanium or zirconium compounds such as oxy-compounds. On the other hand, solutions of tetravalent compounds of titanium or zirconium, if diluted, are susceptible to hydrolysis. It is thus preferable in the present process to employ concentrations of these solutions lying in the neighborhood of the saturation point.

According to the invention, the hydrolysis of tetravalent titanium and zirconium salt is carried out at a temperature lower than 10 C. In the course of the alkaline hydrolysis, the temperature of the hydrolyte increases substantially and if the reaction temperature should become higher than 10 C., the produced hydroxides would provide such chemically inactive acids as meta-titanic acid or meta-zirconic acid, which adversely affects the production of the desired stable addition compounds with hydrogen peroxide.

According to the invention, the hydrolysis is carried out under suflicient cooling to produce highly reactive hydroxides or ortho-titanic or ortho-zirconic acid, thus capable of producing stable addition compounds with hydrogen peroxide. When the thus produced hydroxides are brought into reaction with the equivalent quantity of hydrogen peroxide, a paste-like substance consisting of titanium or zirconium hydroxide-hydrogen peroxide addition compound is formed, as the case may be.

3,139,325 Patented June 30, 1964 ice j In the process according to the invention, 1-5 of sodium pyrophosphate is added in the above mentioned stage to the hydrogen peroxide, which measure constitutes a feature of the invention. It was now found that the pyrophosphatereacts with hydrogen peroxide to form the peroxide of sodium pyrophosphate, which serves for stabilization of the titanium compound.

The above mentioned additional compounds dissolve in an alkaline solution to form the peroxide of sodium pertitanate or perziconate, as the case may be. The addition compounds are not only highly stable and persist for long intervals, but also dissolve stably in an alkaline coating bath containing cadmium or zinc, from which the desired alloy coating containing titanium or zirconium can be produced in the conventional way.

The invention can be more fully understood with reference to the following several examples:

Example 1 A saturated aqueous solution of titanium tetrafluoride was ice-cooled and kept at a temperature lower than 5 C. An equivalent quantity of caustic soda was added and the resulting mixture was permitted to hydrolyze. The thus produced precipitate was then filtered and mixed with an equivalent quantity of hydrogen peroxide (of 35% concentration) containing 5% of sodium pyrophosphate, thus forming titanium hydroxide-hydrogen peroxide addition compound, which is highly stable. This addition compound was then dissolved in a conventional cyanate bath containing cadmium or zinc, therefrom a titantium alloy coating was produced in the conventional way.

Example 2 A saturated aqueous solution of zirconium tetrachloride was ice-cooled and kept at 3 C, and then subjected to hydrolysis in the presence of ammonia and centrifuged. The thus separated precipitate is reacted with an equivalent quantity of hydrogen peroxide (of 35% concentration) containing 3% of sodium pyrophosphate, thus forming zirconium hydroxide-hydrogen peroxide addition compound. This compound together with the titanium additional compound obtained in Example 1, was dissolved in a conventional zinc cyanide and subjected to an electrolysis, thus obtaining a ternary alloy coating containing zinc, titanium and zirconium.

Although for the purpose of explaining the invention certain particular examples thereof have been disclosed, obvious modifications will occur to a person skilled in the art, and it is not desired to be limited to the exact details described.

What is claimed and desired to be secured by Letters Patent is:

1. Process for the production of titanium and zirconium addition products particularly suited to be added to a plating bath containing a cyanide selected from the group consisting of cadmium cyanide and zinc cyanide, said process comprising: preparing a substantially saturated aqueous solution of a salt of a tetravalent metal selected from the group consisting of titanium and zirconium, said salt being selected from the group consisting of the fluorides, chlorides and sulfates of said tetravalent metal; adding an alkali selected from the group consisting of alkali metal hydroxides and ammonium hydroxide to said aqueous salt solution while maintaining the solution and resulting products at a temperature below 10 C.; physically separating the thereby produced precipitated hydroxide from the remaining liquid; then reacting said hydroxide with a chemically equivalent quantity of hydrogen peroxide in the presence of between 1% and 5% by weight of sodium pyrophosphate based on the hydrogen peroxide; and recovering the metal hydroxide-hydrogen peroxide addition product, so produced.

a a 4, 2. The process of claim 1, where in the salt is titanium 2,150,060 Guttenberg et a1 Mar. 7, 1939 tetrafiuoride. 2,333,444 Robinson Nov. 2, 1943 3. The process of claim 1 wherein the salt is zir- OTHER REFERENCES coniurn tetrachloride.

4. The process of claim" 1 wherein the hydrolysis is 5 Mellon Comprehensive Treatls? 011 Inorganlc arm carried out in the presence of caustic soda addedto said B hcal CheImstry, Longmans, Green and Co., New York, aqueous salt sslution. V 1927, vol. VII, pages 130 t0.132.

Schurnb et aL: Hydrogen Peroxide, Reinhold Publish- References Clted the file of this Patent ing Corporation, New York, No. 128, pages 540 and UNITED STATES PATENTS 10 541 (-1955). Blumenthal: The Chemical Behavior of Zirconium, 1,624,162 Boer P 1927 D. Van Nostrand Co., 111e,, New York, 1958, pages 198- 2,1'41,1s9 Lind Dec.27,1938 2m 

1. PROCESS FOR THE PRODUCTION OF TITANIUM AND ZIRCONIUM ADDITION PRODUCTS PARTICULARLY SUITED TO BE ADDED TO A PLATING BATH CONTAINING A CYANIDE SELECTED FROM THE GROUP CONSISTING OF CADMIUM CYANIDE AND ZINC CYANIDE, SAID PROCESS COMPRISING: PREPARING A SUBSTANTIALLY SATURATED AQUEOUS SOLUTION OF A SALT OF A TETRAVALENT METAL SELECTED FROM THE GROUP CONSISTING OF TITANIUM AND ZIRCONIUM, SAID SALT BEING SELECTED FROM THE GROUP CONSISTING OF THE FLUORIDES, CHLORIDES AND SULFATES AND SAID TETRAVALENT METAL; ADDING AN ALKALI SELECTED FROM THE GROUP CONSISTING OF ALKALI METAL HYDROXIDES AND AMMINOUM HYDROXIDE TO SAID AQUEOUS SALT SOLUTION WHILE MAINTAINING THE SOLUTION AND RESULTING PRODUCTS AT A TEMPERATURE BELOW 10*C.; PHYSICALLY SEPARATING THE THEREBY PRODUCED PRECIPITATED HYDROXIDE FROM THE REMAINING LIQUID; THEN REACTING SAID HYDROXIDE WITH A CHEMICALLY EQUIVALENT QUANTITY OF HYDROGEN PEROXIDE IN THE PRESENCE OF BETWEEN 1% AND 5% BY WEIGHT OF SODIUM PYROPHOSPHATE BASED ON THE HYDROGEN PEROXIDE; AND RECOVERING THE METAL HYDROXIDE-HYDROGEN PEROXIDE ADDITION PRODUCT, SO PRODUCED. 